Apoptosis Of Follicular Cells Research Articles

Quercetin ameliorates oxidative stress-induced apoptosis of granulosa cells in dairy cow follicular cysts by activating autophagy via the SIRT1/ROS/AMPK signaling pathway

BackgroundFollicular cysts contribute significantly to reproductive loss in high-yield dairy cows. This results from the death of follicular granulosa cells (GCs) caused by oxidative stress. Quercetin is known to have significant antioxidant and anti-apoptotic effects. However, the effect of quercetin on follicular cysts has yet been elucidated. Therefore, this study aimed to explore the anti-oxidant and anti-apoptosis effects and potential molecular mechanisms of quercetin in H2O2-induced primary cow GCs and 3-nitropropionic acid (3-NPA)-induced mouse model of oxidative stress and thus treat ovarian cysts in dairy cows.ResultsIn this study, compared with estrus cows, cows with follicular cysts showed heightened levels of oxidative stress and increased follicular cell apoptosis, while autophagy levels were reduced. A model of oxidative stress was induced in vitro by H2O2 and showed significant increases in apoptosis together with reduced autophagy. These effects were significantly ameliorated by quercetin. Effects similar to those of quercetin were observed after treatment of cells with the reactive oxygen species (ROS) inhibitor N-acetylcysteine (NAC). Further investigations using chloroquine (autophagy inhibitor), rapamycin (autophagy activator), selisistat (SIRT1 inhibitor), and compound C (AMPK inhibitor) showed that chloroquine counteracted the effects of quercetin on oxidative stress-induced apoptosis, while rapamycin had the same effect as quercetin. In addition, the SIRT1/AMPK pathway inhibitors antagonized quercetin-mediated mitigation of the effects of oxidative stress on increased apoptosis and reduced autophagy. Consistent with the results in vitro, in mouse ovarian oxidative stress model induced by 3-NPA, quercetin activated autophagy through the SIRT1/AMPK signaling pathway, while alleviating oxidative stress damage and inhibiting apoptosis in mouse ovaries.ConclusionsThese findings indicate that quercetin can inhibit apoptosis in GCs and restore ovarian function by activating autophagy through the SIRT1/ROS/AMPK signaling pathway, suggesting a new direction for the treatment of ovarian follicular cysts in high-yield dairy cows.

MiR-7 promotes apoptosis and autophagy of granulosa cells by targeting KLF4 via JAK/STAT3 signaling pathway in chickens

Granulosa cell (GC) death, which leads to follicular atresia, primarily occurs through apoptosis and autophagy. miRNAs are known to be key regulators of autophagy and apoptosis. Although miR-7 acting as a key regulator of follicular atresia, its precise role in granulosa cell autophagy and apoptosis remains to be fully elucidated. In this study, we found that miR-7 was highly expressed in the follicle based on qPCR analysis. Subsequently, transfection of miR-7 inhibitors and mimics downregulated or upregulated the expression of miR-7 and promoted autophagic and apoptotic processes in chicken follicle granulosa cells. Mechanistically, through dual-luciferase reporter gene assays, we validated that KLF4 is a target gene of miR-7. Contrarily, KLF4 was found to negatively regulate autophagy and apoptosis in follicular granulosa cells as evidenced by genetic intervention of KLF4 silencing and overexpression. Furthermore, JAK/STAT3 signaling pathway was confirmed to mediate the regulation of miR-7-KLF4 axis on GC autophagy and apoptosis. These findings offer evidences of the crucial involvement of the miR-7-KLF4 signaling axis in determining autophagy and apoptosis of GCs. This study could offer an important theoretical basis for the use of molecular-assisted breeding in chickens.

FSH induces apoptosis in follicular granulosa cells of Tianzhu white yak and regulates the expression of Fas/FasL mRNA.

The Tianzhu white yak, a globally rare species, holds immense value as a source for yak materials. While the Fas/FasL pathway is pivotal in granulosa cells apoptosis, its precise molecular workings remain enigmatic. This study endeavours to decipher the role of follicle-stimulating hormone (FSH) in suppressing ovarian granulosa cells (GC) apoptosis in the Tianzhu white yak. Utilizing advanced cell culture techniques, we employed the MTT method, flow cytometry, fluorescence labelling and RT-PCR to investigate the apoptotic effects of FSH on yak GCs. Our results reveal that FSH's inhibitory effect on GC apoptosis follows a normal distribution pattern, peaking at an FSH concentration of 100 ng/mL with an apoptosis inhibition rate of 89.31%. When serum was withdrawn, an FSH concentration of 2 × 106 ng/mL reduced apoptosis by 72.84%. Annexin V-FITC staining revealed membrane invaginations, bubble and protrusion formation on the cell surface, and alterations in membrane structure and cell morphology. Flow cytometry analysis further demonstrated that FSH administration prior to early granulosa cell apoptosis had a more profound effect than during gradual apoptosis, both showing a suppressive effect on early follicular granulosa cell apoptosis. A transcription-level analysis conducted 3 h prior to serum withdrawal, with the addition of 100 ng/mL FSH, revealed intricate regulations in the expression of Fas/FasL. Notably, we observed a gradual increase in FasL expression over time, yet the presence of FSH effectively down-regulated FasL expression to baseline levels, without notable changes in Fas expression. Immunocytochemical analysis further confirmed the presence of both Fas and FasL on the cell membrane, nucleus and cytoplasm, with varying intensities depending on the duration of FSH treatment. Our findings suggest that FSH may suppress the apoptotic pathway in follicular primarily by down-regulating FasL expression, indicating that Fas-regulated mitochondrial pathways play a more prominent role compared to death receptor pathways. This study offers a fresh perspective on the mechanism underlying follicular atresia in Tianzhu white yaks and lays a solid theoretical foundation for the expansion of this endangered species' population.

Titanium dioxide nanoparticles Disrupt ultrastructure and function of Rat thyroid tissue via oxidative stress

Nano-TiO2 is widely used in various fields such as industry, daily necessities, food and medicine. Previous studies have shown that it can enter mammalian tissues through the digestive tract or respiratory tract and have effects on various organs and systems. However, the effect of nano-TiO2 on the mammalian thyroid gland has not been reported. In this study, we fed SD rats with rutile nano-TiO2 at a dose of 5 mg/kg body weight for 3 weeks, and then examined the thyroid histology and thyroid function of the rats. In vitro experiments were conducted to determine the effects of nano-TiO2 on the viability, apoptosis, inflammatory factors, antioxidant enzymes, and oxidative stress of human thyroid follicular epithelial cells. Histological evidence showed abnormal morphology of rat thyroid follicles and organelle damage in follicular epithelial cells. Nano-TiO2 caused a decrease in the level of sodium/iodide symporter (NIS), an increase in the level of apoptotic protein cleaved-caspase 3, and an increase in the levels of pro-inflammatory factors IL-1β and TNF-α in rat thyroid tissue. Nano-TiO2 also resulted in increased serum FT4 and TPO-Ab levels. In in vitro experiments, nano-TiO2 reduced the viability of human thyroid follicular cells, downregulated the levels and activities of antioxidant enzymes CAT, GPX1 and SOD, and increased the levels of ROS and MDA caused by oxidative stress. These results indicate that nano-TiO2 damages the structure and function of thyroid follicular epithelial cells through oxidative stress. Long-term exposure to nano-TiO2 could be a potential risk factor for thyroid dysfunction.

Melatonin alleviates endoplasmic reticulum stress and follicular granulosa cell apoptosis by regulating ATF4 to activate mTOR signaling pathway in chickens

Follicular atresia in chickens reduces the number of follicles that can further develop, leading to decrease egg laying. Endoplasmic reticulum stress (ERS) can initiate a unique pathway inducing the apoptosis of follicular granulosa cells, thus reducing egg laying. Melatonin (MEL) is involved in the regulation of follicle development, ovulation, and oocyte maturation, and is closely related to follicle fate. Mammalian target of Rapamycin (mTOR) signaling pathway plays an important role in cell growth regulation, and that there is a possible crosstalk between melatonin and mTOR activity in granular cells maturation and ovulation. This study aimed to investigate whether MEL inhibits ERS and follicular granulosa cell apoptosis by regulating ATF4 to activate mTOR signaling pathway in chickens. Frist, we established an in vitro ERS cell model using tunicamycin (TM). The results showed that different concentrations of TM exhibited dose-dependent inhibition of cell activity and induction of granulosa cells (P<0.01). Therefore, we chose 5 µg/mL of TM and a treatment time for 6 h as the optimal concentration for the following experiments. Then we investigate whether melatonin can inhibit ERS. TM treatment decreased the cell viability and Bcl-2 expression, increasing ROS levels and the mRNA expression of Grp78, ATF4, CHOP, PERK, eIF-2α, and BAX (P<0.01), whereas TM+MEL treatment significantly inhibited these changes (P<0.01). Then we explored whether melatonin protects follicular granulosa cells from ERS-induced apoptosis through the mammalian target of rapamycin (mTOR) signaling pathway by regulating ATF4, We found that ATF4 knockdown inhibited ERS by decreasing the expression of ERS-related genes and proteins and activating mTOR signaling pathway by increasing the protein expression of p4E-BP1 and pT389-S6K (P<0.001), while these changes were promoted by TM+si-ATF4+MEL treatment (P<0.01). These results indicate that MEL could alleviate TM-induced ERS by regulating ATF4 to activate mTOR signaling pathway in follicular granulosa cells, thus providing a new perspective for prolonging the laying cycle in chickens.

Effects of ferritin heavy chain on oxidative stress, cell proliferation and apoptosis in geese follicular granulosa cells

ABSTRACT 1. The ferritin heavy chain (FHC) has a vital impact on follicular development in geese, due to its ability to regulate apoptosis of granulosa cells (GCs) and follicular atresia. However, its specific regulatory mechanisms remain unclear. The present study characterised how FHC regulates oxidative stress, cell proliferation and apoptosis in goose GCs by interfering with and overexpressing the FHC gene. 2. After 72 h of interference with FHC expression, the activity of GCs decreased remarkably (p < 0.05), reactive oxygen species (ROS) levels and the expression levels of antioxidant enzyme genes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) increased significantly (p < 0.05). The overexpression of FHC for 72 h was found to significantly reduce the expression of CAT and SOD genes (p < 0.05). 3. Interfering with FHC expression revealed that the expression levels of the cell proliferation gene Aurora kinase A (AURORA-A) were significantly decreased (p < 0.05), while the expression levels of the apoptosis genes B-cell lymphoma-2 (BCL-2) and cysteine aspartate-specific protease 8 (CASPASE 8) increased (p < 0.05). Further research has shown that, when interfering with FHC expression for 72 h, apoptosis rate increased by 1.19-fold (p < 0.05), but the current data showed a lower apoptosis rate after FHC overexpression by 59.41%, 63.39%, and 52.31% at three different treatment times (p < 0.05). 4. In conclusion, FHC improved the antioxidant capacity of GCs, promotes GCs proliferation, and inhibits GCs apoptosis of ovarian follicles in Sichuan white geese.

MiR-128-3p Regulates Follicular Granulosa Cell Proliferation and Apoptosis by Targeting the Growth Hormone Secretagogue Receptor.

The proliferation and apoptosis of granulosa cells (GCs) affect follicle development and reproductive disorders, with microRNAs playing a crucial regulatory role. Previous studies have shown the differential expression of miR-128-3p at different stages of goat follicle development, which suggests its potential regulatory role in follicle development. In this study, through the Cell Counting Kit-8 assay, the EDU assay, flow cytometry, quantitative real-time polymerase chain reaction, Western blot, and the dual-luciferase reporter assay, we used immortal human ovarian granulosa tumor cell line (KGN) cells as materials to investigate the effects of miR-128-3p and its predicted target gene growth hormone secretagogue receptor (GHSR) on GC proliferation and apoptosis. The results show that overexpression of miR-128-3p inhibited the proliferation of KGN cells, promoted cell apoptosis, and suppressed the expression of proliferating cell nuclear antigen (PCNA) and B-cell lymphoma-2 (BCL2) while promoting that of Bcl-2 associated X protein (BAX). The dual-luciferase reporter assay revealed that miR-128-3p bound to the 3' untranslated region sequence of GHSR, which resulted in the inhibited expression of GHSR protein. Investigation of the effects of GHSR on GC proliferation and apoptosis revealed that GHSR overexpression promoted the expression of PCNA and BCL2, enhanced GC proliferation, and inhibited cell apoptosis, whereas the opposite effects were observed when GHSR expression was inhibited. In addition, miR-128-3p and GHSR can influence the expression of extracellular signal-regulated kinase 1/2 protein. In conclusion, miR-128-3p inhibits KGN cell proliferation and promotes cell apoptosis by downregulating the expression of the GHSR gene.

Heme Oxygenase-1 Regulates Zearalenone-Induced Oxidative Stress and Apoptosis in Sheep Follicular Granulosa Cells.

Zearalenone (ZEA) is a common non-steroidal estrogenic mycotoxin found in a range of animal feeds and poses a serious threat to the reproductive health of farm animals and humans. However, the mechanism underlying ZEA-induced reproductive toxicity in sheep remains unknown. Granulosa cells are crucial for egg maturation and the fertility of female sheep. In this study, we aimed to examine the impact of different ZEA concentrations on sheep follicular granulosa cells and to elucidate the potential molecular mechanism underlying ZEA-induced toxicity using transcriptome sequencing and molecular biological approaches. Treating primary sheep follicular granulosa cells with different concentrations of ZEA promoted the overproduction of reactive oxygen species (ROS), increased lipid peroxidation products, led to cellular oxidative stress, decreased antioxidant enzyme activities, and induced cell apoptosis. Using transcriptome approaches, 1395 differentially expressed genes were obtained from sheep follicular granulosa cells cultured in vitro after ZEA treatment. Among them, heme oxygenase-1 (HMOX1) was involved in 11 biological processes. The protein interaction network indicated interactions between HMOX1 and oxidative and apoptotic proteins. In addition, N-acetylcysteine pretreatment effectively reduced the ZEA-induced increase in the expression of HMOX1 and Caspase3 by eliminating ROS. Hence, we suggest that HMOX1 is a key differential gene involved in the regulation of ZEA-induced oxidative stress and apoptosis in follicular granulosa cells. These findings provide novel insights into the prevention and control of mycotoxins in livestock.

Genistein ameliorates starvation-induced porcine follicular granulosa cell apoptosis.

Genistein is an isoflavone which is beneficial for health, but little is known regarding its function on granulosa cell fate during follicular atresia. In the present study, we established an in-vitro model of porcine follicular granulosa cell apoptosis by serum-deprivation and showed that treatments with 1 μM and 10 μM genistein significantly reduced the apoptotic rate of granulosa cells compared to the blank control (p < 0.05). These results suggest that genistein at micromolar levels alleviates serum deprivation-induced granulosa cell apoptosis, and the ameliorative effect of genistein on granulosa cell apoptosis is likely to be able to inhibit nutrient depletion-induced follicular atresia. Further experimental results revealed that the expression of the autophagic marker protein LC3II in 100 nM - 10 μM genistein treatment increased in a dose-dependent manner and was higher than the control (p < 0.05). Genistein also dose-dependently promoted the phosphorylation of AMPK (adenosine 5'-monophosphate [AMP]-activated protein kinase) in granulosa cells. Poly(ADP-ribose) (pADPr) formation in genistein-treated groups was also notably higher than in the controls (p < 0.05). Collectively, genistein alleviates serum deprivation-induced granulosa cells in vitro through enhancing autophagy, which involving AMPK activation and PARylation signaling. However, further study should be taken to investigate the role of the above signaling on this process.

Targeting hnRNPC suppresses thyroid follicular epithelial cell apoptosis and necroptosis through m6A-modified ATF4 in autoimmune thyroid disease

Both environmental and genetic factors contribute to the etiology of autoimmune thyroid disease (AITD) including Graves’ disease (GD) and Hashimoto’s thyroiditis (HT). However, the exact pathogenesis and interactions that occur between environmental factors and genes remain unclear, and therapeutic targets require further investigation due to limited therapeutic options. To solve such problems, this study utilized single-cell transcriptome, whole transcriptome, full-length transcriptome (Oxford nanopore technology), and metabolome sequencing to examine thyroid lesion tissues from 2 HT patients and 2 GD patients as well as healthy thyroid tissue from 1 control subject. HT patients had increased ATF4-positive thyroid follicular epithelial (ThyFoEp) cells, which significantly increased endoplasmic reticulum stress. The enhanced sustained stress resulted in cell death mainly including apoptosis and necroptosis. The ATF4-based global gene regulatory network and experimental validation revealed that N6-methyladenosine (m6A) reader hnRNPC promoted the transcriptional activity, synthesis, and translation of ATF4 through mediating m6A modification of ATF4. Increased ATF4 expression initiated endoplasmic reticulum stress signaling, which when sustained, caused apoptosis and necroptosis in ThyFoEp cells, and mediated HT development. Targeting hnRNPC and ATF4 notably decreased ThyFoEp cell death, thus ameliorating disease progression. Collectively, this study reveals the mechanisms by which microenvironmental cells in HT and GD patients trigger and amplify the thyroid autoimmune cascade response. Furthermore, we identify new therapeutic targets for the treatment of autoimmune thyroid disease, hoping to provide a potential way for targeted therapy.

Qirong Tablets inhibits apoptosis of ovarian granulosa cells via PI3K/Akt/ HIF-1 signaling pathway

This study aims to observe the effect and explore the mechanism of Qirong Tablets in the treatment of premature ovarian insufficiency(POI) in mice via the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)/hypoxia inducible factor 1(HIF-1) signaling pathway. Sixty SPF female BALB/c mice were randomly divided into normal group, model group, positive control group, Qirong Tablets low-, medium-and high-dose group. The normal group was intraperitoneally injected with the same amount of normal saline, and the other groups were intraperitoneally injected with cyclophosphamide 120 mg·kg~(-1)·d~(-1) once to establish a POI animal model. After the model was successfully established, the low-, medium-and high-dose groups of Qirong Tablets were administered orally with 0.6, 1.2, 2.4 mg·kg~(-1)·d~(-1) respectively. The positive control group was given 0.22 mg·kg~(-1)·d~(-1) Clementine Tablets by intragastric administration, and the normal group and model group were given intragastric administration with the same amount of normal saline, and the treatment was 28 d as a course of treatment. After drug intervention, enzyme-linked immunosorbent assay(ELISA) was employed to measure the levels of estradiol(E_2), follicle-stimulating hormone(FSH), luteinizing hormone(LH), and anti-mullerian hormone(AMH) in peripheral blood, and hematoxylin-eosin(HE) staining to observe the ovarian tissue. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL) assay was used to detect the apoptosis of granulosa cells, and Western blot to determine the expression levels of B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), caspase-3, PI3K, Akt, and HIF-1. Compared with the normal group, the modeling of POI caused loose or destroyed ovarian tissue with vacuolar structures, edema and fibrosis in the ovarian interstitium, disordered or loose arrangement of granulosa cells, and reduced normal follicles. Compared with the model group, drug interventions restored the ovarian tissue and follicles at all the development stages and reduced atretic follicles. Compared with the normal group, the modeling of POI lowered the serum level of E_2 and AMH(P&lt;0.01), and elevated the level of FSH and LH(P&lt;0.01). Compared with the model group, high-dose Qirong Tablets elevated the levels of E_2 and AMH(P&lt;0.05), and lowered the levels of FSH and LH(P&lt;0.05). Compared with the normal group, the modeling of POI up-regulated the protein levels of PI3K, Akt, HIF-1, Bax, and caspase-3 and down-regulated the protein level of Bcl-2 in the ovarian tissue(P&lt;0.01). Compared with the model group, low-, medium-, and high-dose Qirong Tablets down-regulated the protein levels of PI3K, Akt, HIF-1, Bax, and caspase-3 proteins and up-regulated the protein level of Bcl-2 in the ovarian tissue(P&lt;0.05). In conclusion, Qirong Tablets can up-regulate the expression Bcl-2, down-regulate the expression of Bax and caspase-3 in POI mice. Qirong Tablets may inhibit the apoptosis of follicular granulosa cells in mice, thereby delaying ovarian aging, improving reproductive axis function, and strengthening ovarian reserve capacity, which may be associated with the inhibition of PI3K/Akt/HIF-1 pathway.

Serotonin Transporter Activity in Mouse Oocytes Is a Positive Indicator of Follicular Growth and Oocyte Maturity.

Serotonin (5-hydroxytryptamine, 5-HT) is known to be a regulator of oocyte maturation in a large number of animal species. In maturing mammalian oocytes, the accumulation of exogenous, maternal serotonin occurs due to the activity of the membrane transporter SERT. In this work, we investigated how SERT activity in oocytes correlates with indicators of follicular selection and oocyte maturity. An immunohistochemical study showed that the difference in the 5-HT intake activity in oocytes does not correlate with the marker of apoptosis in follicular cells, but positively correlates with markers of follicular growth, such as granulosa proliferation and follicle size. Functional analysis of oocytes at different stages of maturation showed that the expression and activity of SERT increases with oocyte maturation. An in vivo experiment on administration of the selective serotonin reuptake inhibitor fluoxetine (20 mg/kg) for 7 days showed a significant decrease in the content of serotonin in both growing GV-oocytes and ovulated mature MII-oocytes. The data obtained clearly indicate that the mechanism of specific membrane transport of serotonin normally ensures the accumulation of serotonin in maturing oocytes, and can be considered as a promising positive marker of their mature status.

Ferritin heavy chain participated in ameliorating 3-nitropropionic acid-induced oxidative stress and apoptosis of goose follicular granulosa cells

Oxidative stress is the major culprits responsible for ovarian dysfunction by damaging granulosa cells (GCs). Ferritin heavy chain (FHC) may participate in the regulation of ovarian function by mediating GCs apoptosis. However, the specific regulatory function of FHC in follicular GCs remains unclear. Here, 3-nitropropionic acid (3-NPA) was utilized to establish an oxidative stress model of follicular GCs of Sichuan white geese. To explore the regulatory effects of FHC on oxidative stress and apoptosis of primary GCs in geese by interfering or overexpressing FHC gene. After transfection of siRNA-FHC to GCs for 60 h, the expressions of FHC gene and protein decreased significantly (P < 0.05). After FHC overexpression for 72 h, the expressions of FHC mRNA and protein upregulated considerably (P < 0.05). The activity of GCs was impaired after interfering with FHC and 3-NPA coincubated (P < 0.05). When overexpression of FHC combined with 3-NPA treatment, the activity of GCs was remarkably enhanced (P < 0.05). After interference FHC and 3-NPA treatment, NF-κB and NRF2 gene expression decreased (P < 0.05), the intracellular reactive oxygen species (ROS) level increased greatly (P < 0.05), BCL-2 expression reduced, BAX/BCL-2 ratio intensified (P < 0.05), the mitochondrial membrane potential decreased notably (P < 0.05), and the apoptosis rate of GCs aggravated (P < 0.05). While overexpression of FHC combined with 3-NPA treatment could promote BCL-2 protein expression and reduce BAX/BCL-2 ratio, indicating that FHC regulated the mitochondrial membrane potential and apoptosis of GCs by mediating the expression of BCL-2. Taken together, our research manifested that FHC alleviated the inhibitory effect of 3-NPA on the activity of GCs. FHC knockdown could suppress the expression of NRF2 and NF-κB genes, reduce BCL-2 expression and augment BAX/BCL-2 ratio, contributing to the accumulation of ROS and jeopardizing mitochondrial membrane potential, as well as exacerbating GCs apoptosis.

Selenium Protects Follicular Granulosa Cells from Apoptosis Induced by Mercury Through Inhibition of ATF6/CHOP Pathway in Laying Hens.

The purpose of this research was to explore the effect of selenium on mercury-mediated apoptosis of follicular granulosa cells in laying hens. Moreover, the ATF6/CHOP pathway was investigated to explore the mechanism in this progress. Hg, Se, and 4-phenyl butyric acid were used alone or in combination to treat the cells. Our results showed that the nuclear in cells became condensate after Hg exposure, while Se addition significantly alleviated this change. Hg exposure significantly induced the apoptosis and the reduction of mitochondrial membrane potential in cells (P < 0.05). Nevertheless, co-treatment of Se significantly inhibited these effects (P < 0.05). Additionally, Hg exposure dramatically elevated the gene expressions of Bax/Bcl-2 (P < 0.05), caspase-3 (P < 0.05), caspase-9 (P < 0.05), protein kinase RNA-like endoplasmic reticulum kinase (P < 0.05), activating transcription factor 6 (P < 0.05), C/EBP homologous protein (CHOP; P < 0.05), inositol-requiring enzyme 1α (P < 0.05), tumor necrosis factor-associated factor 2 (P < 0.05), activating transcription factor 6 (ATF6; P < 0.05), and apoptosis signal-regulating kinase 1 (P < 0.05) in cells, whereas Se addition avoided these changes. The exposure to Hg considerably boosted the expression of ATF6 and CHOP protein (P < 0.05), while Se addition significantly alleviated the above-mentioned enhancements (P < 0.05). In summary, Hg exposure induced apoptosis, which was considerably reduced alleviated by Se addition, which was linked to the ATF6/CHOP pathway in follicular granulosa cells in laying hens.

Low-density small extracellular vesicles in bovine follicular fluid carrying let-7i target FASLG to inhibit granulosa cells apoptosis

Apoptosis of granulosa cells is a key factor in mammalian follicular atresia. It has a significant impact on oocyte development and maturation. Extracellular vesicles (EVs) are a group of highly heterogeneous population. Previous studies have found that ovarian follicular fluid is rich in EVs. In the present study, the follicular fluid of 3–5 mm follicles from bovine ovaries without corpus luteum was collected, and a subtype of small EVs (sEVs), low-density small EVs (LD-sEVs), was successfully isolated by differential ultracentrifugation combined with iodixanol density gradient centrifugation. LD-sEVs were identified using transmission electron microscope, nanoparticle tracking analysis and Western blot. Flow cytometry, Quantitative reverse transcription PCR (RT-qPCR), Western blot, and other methods were used to detect the effect of LD-sEVs on follicular granulosa cell apoptosis. After that, let-7i, a highly expressed miRNA component in LD-sEVs, was screened and target validation was carried out in granulosa cells. The results showed that LD-sEVs could be taken up by granulosa cells and inhibited the apoptosis. Further research found that let-7i inhibits the apoptosis of granulosa cells by targeting FASLG. It plays an important role in regulating the apoptosis of follicular granulosa cells, which may affect follicular development.

Integrated transcriptome and proteome revealed that the declined expression of cell cycle-related genes associated with follicular atresia in geese

BackgroundGeese exhibit relatively low reproductive performance, and follicular atresia is an important factor that restricts the egg production of geese. Systematic analysis of the regulation of follicle atresia in geese through transcriptome and proteome levels could provide meaningful information on clarifying the mechanism of follicle atresia in poultry.ResultThe granulosa cell layer was loose, disintegrated and showed apoptosis in atretic follicles and remained intact in normal follicles. The hormone levels of FSH and LH were significantly decreased in the atresia follicles compared to the normal follicles (P < 0.05). A total of 954 differentially expressed genes (DEGs, 315 increased and 639 decreased) and 161 differentially expressed proteins (DEPs, 61 increased and 100 decreased) were obtained in atresia follicles compared to normal follicles, of which, 15 genes were differentially expressed in both transcriptome and proteome. The DEGs were mainly enriched in sodium transmembrane transport, plasma membrane, and transmembrane transporter activity based on the GO enrichment analysis and in the cell cycle pathway based on the KEGG enrichment analysis. The DEPs were mainly enriched in localization, lysosome, and phospholipid-binding based on the GO enrichment analysis. Candidate genes Smad2/3, Smad4, Annexin A1 (ANXA1), Stromelysin-1 (MMP3), Serine/threonine-protein kinase (CHK1), DNA replication licensing factor (MCM3), Cyclin-A2 (CCNA2), mitotic spindle assembly checkpoint protein (MAD2), Cyclin-dependent kinase 1 (CDK1), fibroblast growth factor 12 (FGF12), and G1/S-specific cyclin-D1 (CCND1) were possibly responsible for the regulation of atresia.ConclusionThe cell cycle is an important pathway for the regulation of follicular atresia. Sodium outflow and high expression of MMP3 and MMP9 could be responsible for structural destruction and apoptosis of follicular cells.

Epidermal growth factor regulates autophagy activity and endocytosis of yak cumulus cells in a concentration-dependent manner.

Autophagy and endocytosis are crucial biological activities in mammalian follicle development and oocyte maturation, which are easily affected by external environmental factors. Epidermal growth factor (EGF), as an important component of follicular fluid, regulates the growth and apoptosis of follicular cells. However, its regulatory mechanism of autophagy and endocytosis in mammals, especially in large domestic animals such as plateau yak, remains unclear. This study aimed to investigate the regulatory mechanism of EGF on autophagy and endocytosis in yak cumulus cells. Yak cumulus cells were treated with different concentrations of EGF and appropriate concentrations of EGFR inhibitor gefitinib (10 μM). The dynamic expression levels of Atg5, Beclin1, LC3, Cav1 and Cav2 were detected by immunofluorescence staining, qRT-PCR and Western-blot. EGF inhibited autophagy in yak cumulus cells by down-regulating the expression of Atg5, Beclin1, and LC3. The level of autophagy varied with the concentration of ligands, and the inhibition was most significant at 100 ng/mL. Noteworthy, EGF can promote endocytosis by regulating the expression of Cav1 and Cav2, but the EGFR-mediated signaling pathway is not the main way to regulate the expression of these proteins. These results provide a reference for further exploring the effects of growth factors on livestock germ cells and the regulatory role of autophagy-endocytosis crosstalk mechanism in follicle development and oocyte maturation, to improve the fecundity of yaks.

Integrative analyses of the mRNA expression profile reveal the involvement of STC1 in chicken folliculogenesis.

Efficient ovarian follicle development, maturation, and ovulation are critical for egg production performance. Previous research has underscored the importance of messenger RNAs (mRNAs) in regulating development and folliculogenesis in chicken ovarians. However, the molecular mechanism is not fully understood, especially in the late period of the laying cycle. In the present study, ovarian tissues from 80-week-old Hy-Line Brown layers (three with high and three with low rates of egg laying) were collected for transcriptome sequencing. A total of 306 differentially expressed genes (DEGs) were identified in this study, at a false discovery rate (FDR)-corrected P-value < 0.05 and a log2|fold change| (log2|FC|) ≥1.5. Among these DEGs, stanniocalcin 1 (STC1) was mainly related to cellular processes, single-organism processes, biological regulation, metabolic processes, developmental processes, and reproductive processes. Then, we further investigated the regulation of STC1 during chicken follicle development and found that STC1 inhibited the proliferation and stimulated the apoptosis of follicular granulosa cells (GCs), and decreased the expression of progesterone (P4) and estradiol (E2). Collectively, these results suggest that STC1 plays an important role in chicken follicle development by decreasing GC proliferation and steroidogenesis and stimulating GC apoptosis. This study contributes to the understanding of the reproductive biology of laying hens in the late period of the laying cycle and further lays a foundation for the improvement of egg production in poultry breeding.

MiR-450-5p and miR-202-5p Synergistically Regulate Follicle Development in Black Goat.

Follicle maturation is a complex biological process governed by numerous factors, and researchers have observed follicle development by studying the proliferation and apoptosis of follicular granulosa cells (GCs). However, the regulatory mechanisms of GCs proliferation and death during follicle development are largely unknown. To investigate the regulatory mechanisms of lncRNAs, mRNAs, and microRNAs, RNA sequencing (RNA-seq) and small RNA-seq were performed on large (>10 mm) and small follicles (<3 mm) of Leizhou black goat during estrus. We discovered two microRNAs, miR-450-5p and miR-202-5p, which can target GCs in goats and may be involved in follicle maturation, and the effects of miR-450-5p and miR-202-5p on ovarian granulosa cell lines were investigated (KGN). Using cell counting kit-8 (CCK-8) assays, 5-Ethynyl-2’-deoxyuridine (EdU) assay and flow cytometry, miR-202-5p overexpression could suppress the proliferation and induce apoptosis of GCs, whereas miR-450-5p overexpression induced the opposite effects. The dual-luciferase reporter assay confirmed that miR-450-5p could directly target the BMF gene (a BCL2 modifying factor), and miR-202-5p targeted the BCL2 gene. A considerable rise in phosphorylated Akt (p-AKT) protein was observed following the downregulation of BMF by miR-450-5p mimics. After BMF gene RNAi therapy, a notable elevation in p-AKT was detected. Mimics of miR-202-5p inhibited BCL2 protein expression, significantly decreasing p-AMPK protein expression. These results imply that during the follicular development in black goats, the miR-450-5p-BMF axis favored GC proliferation on a wide scale, while the miR-202-5p-BCL2 axis triggered GC apoptosis.

MiR-34a-5p promotes autophagy and apoptosis of ovarian granulosa cells via the Hippo-YAP signaling pathway by targeting LEF1 in chicken

Follicular atresia is a natural physiological phenomenon in poultry reproduction. It is well known that follicular atresia is caused by both autophagy and apoptosis of granulosa cells. In current experiment, we evaluated the function of miR-34a-5p on autophagy and apoptosis in chicken follicular atresia. First, the follicular atresia model of chicken was successfully constructed by subcutaneous injection of tamoxifen (TMX), and found the expression of miR-34a-5p in the atresia follicles obviously increased. Then, we confirmed that miR-34a-5p accelerates autophagy and apoptosis of chicken granulose cells in vitro, and miR-34a-5p could induce apoptosis by mediating autophagy. Mechanistically, lymphoid enhancer binding factor 1 (LEF1) was deemed as a target gene for miR-34a-5p. On the contrary, LEF1 overexpression attenuated the autophagy and apoptosis of chicken granular cells. In addition, it was confirmed that the miR-34a-5p/LEF1 axis plays a regulatory role in chicken granulosa cells by mediating the Hippo-YAP signaling pathway. Taken together, this study demonstrated that miR-34a-5p contributes to autophagy and apoptosis of chicken follicular granulosa cells by targeting LEF1 to mediate the Hippo-YAP signaling pathway.